Q: A sodium street lamp emits yellow light with a wavelength of $589\ \mathrm{nm}$. What is the frequency of this light? (Speed of light $c = 3.00 \times 10^8\ \mathrm{m/s}$)

$5.09 \times 10^{14}\ \mathrm{Hz}$

Question 1

Which of the following statements best explains why the photoelectric effect could not be explained by classical wave theory?

Accepted Answer

Classical wave theory predicted that electrons would be emitted at any light intensity, regardless of frequency.

Question 2

A sodium street lamp emits yellow light with a wavelength of $589\ \mathrm{nm}$. What is the frequency of this light? (Speed of light $c = 3.00 	imes 10^8\ \mathrm{m/s}$)

Accepted Answer

$5.09 	imes 10^{14}\ \mathrm{Hz}$

Question 3

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number $l$

Question 4

According to the Bohr model, what happens when an electron in a hydrogen atom transitions from $n=4$ to $n=2$?

Accepted Answer

A photon is emitted with energy equal to the difference between the two energy levels.

Question 5

Which of the following sets of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

$n=2,\ l=2,\ m_l=0,\ m_s=+\frac{1}{2}$

Question 6

Which principle states that no two electrons in an atom can have the same set of four quantum numbers?

Accepted Answer

Pauli Exclusion Principle

Question 7

What is the condensed electron configuration for selenium (Se, atomic number 34)?

Accepted Answer

$[\mathrm{Ar}]\ 4s^2\ 3d^{10}\ 4p^4$

Question 8

Which of the following best describes the difference between core electrons and valence electrons?

Accepted Answer

Core electrons are those in filled inner shells, while valence electrons are in the outermost shell and participate in chemical bonding.

Question 9

A certain element has the electron configuration $[\mathrm{Ar}]\ 4s^2\ 3d^5$. Which element is this, and why is this configuration considered an anomaly?

Accepted Answer

Chromium; because half-filling the $d$ subshell is more stable than the expected configuration.

Question 10

Which equation correctly relates the wavelength $\lambda$ of a particle to its mass $m$ and velocity $v$ according to de Broglie?

Accepted Answer

$\lambda = \frac{h}{mv}$

Question 11

Which of the following statements about $p$ orbitals is correct?

Accepted Answer

$p$ orbitals have two lobes with a node at the nucleus.

Question 12

If an electron in a hydrogen atom absorbs a photon and moves from $n=2$ to $n=5$, what is the sign of $\Delta E$ and what does it represent?

Accepted Answer

$\Delta E$ is positive; energy is absorbed.

Question 13

Which quantum number(s) determine the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number $m_l$

Question 14

Which rule states that electrons fill degenerate orbitals singly before pairing up?

Accepted Answer

Hund's Rule

Question 15

What is the maximum number of electrons that can occupy the $3d$ subshell?

Accepted Answer

10

Question 16

Which of the following best describes the Heisenberg Uncertainty Principle?

Accepted Answer

It is impossible to know both the exact position and momentum of a particle simultaneously.

Question 17

Which of the following statements about the energy of orbitals in many-electron atoms is correct?

Accepted Answer

Orbitals in the same principal energy level do not necessarily have the same energy due to electron-electron repulsion.

Question 18

Which of the following is the correct order of filling for the following orbitals: $4s$, $3d$, $4p$?

Accepted Answer

$4s \rightarrow 3d \rightarrow 4p$

Question 19

Which of the following best describes a 'degenerate' set of orbitals?

Accepted Answer

Orbitals that have the same energy.

Chapter 6: Electronic Structure of Atoms – Study Notes

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